Cable-served wiring apparatus



Dec. 29, 1942. v. R. DESPARD 2,306,596

`GABLE-SERVED WIRING APPARATUS Filed Oct. 4, 1939 5 Sheets-Sheet 2 43J.- 4@ 4a 405455 47' y F2 4. 4@ 47 Dec. 29, 1942. jv. R. DESPARD2,306,596

CABLEN SERVED WIRING APPARATUS Filed Oct. 4, 19259 5 Sheets-Sheet 3CQM/MMM@ Amrwy Dec. 29, 1942. v R, DESPARD CABLE-SERVED WIRING APPARATUS5 Sheets-Sheet 4 Filed Oct. 4, y1939 InverJ/Or Vic/Vor R Vaspaw Dw.,29s, ma., V, R, @ESE-ARD 2,306,596

CABLE SERVED WIRING APPARATU S Filed OCb. 4, 1959 5 Sheets-Sheet 5vill/l. M.-

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Invemor Patented Dec. 29, 1942 CABLE-SERVED wmmc. APPARATUS Victor R.Despard, Syracuse, N. Y., assignor to Pass & Seymour, Inc., Syracuse, N.Y., a corporation o! New York Application October 4, 1939, Serial No.297,907

' (c1. 17a-33s) 13 claims.

My invention relates to cable-served 'wiring apparatus for exposed orsurface" installation in buildings, and has for a general object toprovide a line of wiring-units, including switches, lampreceptacles andother items, all characterized by novel structure of my invention thatmakes them particularly appropriate for use in cottages, farmhouses,shops and other buildings that commonly are of wood-framed construction,and to be used in conjunction with heavily-sheathed, flexible,multiple-conductor cable, commonly of metal-sheathed or armored type,which also is surface mounted, as the wiring-proper that serves them.

In the electriflcation of the general class of modest-cost buildingsmentioned, in which minimizing of the installed cost of the wiring andits permanent wiring-devices connected therein is an importantdesideratum,the safety of a cablewired job against various hazards isnormally a prime reason for its preference by the owner (where choice isopen) over the cheaper knoband-tube type of surface installation, inwhich individual strands of insulated wire are strung on insulatingknobs or cleats mounted on the woodwork and run through porcelain tubeswhere woodwork has to be passed through; but the neater appearance of acable-wire job is another factor, and often a determining one, in thechoice.

A further general object of my invention is, therefore, to provide, inthe wiring-units in which it is embodied, an intrinsic neatness, and aneat and novel co-operation with the heavy cable, that greatly bettersthe appearance of the installed job as compared with prior types ofinstallations, and

Another and important general object thereof is so to novelly constructthe wiring-units that, in the installation thereof in conjunction withsuch appropriate cable, costs of both the materials used and the laborrequired may be substantially reduced, as against any priortype ofcable-served surface installation of which I am aware.

Prior to my invention it has been a standard practice, in installingcable-served wiring-devices as part of the permanent electrical'facilitiesof the building-and still is, save Where equipment accordingto my present invention is used-to provide an outlet-box or switch box,mounted on the framing or on a wall surface, at each point where aswitch, lamp-receptacle or other wiringdevice is to be installed, and tomount the selected wiring-device in the face orifice of the box aftersaid wiring-device has had its bindingposts or terminals duly connectedwith appropriate wires of the cable; the outlet-box being generally ametal one, and necessarily so under safety-requirements where the cableemployed is of armored or metal-sheathed type.

Another general object of my invention is so to construct all thewiring-units making up an appropriate line as aforesaid, that need forand use of an outlet-box is done away with, without sacrifice of safetywhere metal-sheathed cable is employed; this elimination of theoutlet-boxes being important to the reduction of materialscost and thebetterment of appearance of the installation, that I attain.

Further, in said prior practice the footage of cable required on any jobis greater than the sum of the center-to-center distances between thewiring-devices to be served, each section of cable that is to connecttwo wiring-devices needing to be cut substantially a foot longer thanthe-ce`n` ter-to-center spacing of their outlet-boxes; for although thecables sheath need only enter a wall port of each box far enough -to beclamped therein, its solid, single-strand conductors-desheathed back tothe clamp and with the insulation stripped from their ends-must extendout through the face orifice of each box some six inches, to give theelectrician hand-room to conneet the wiring-devices to suitable ones ofthe bared wire-ends; the ends of any wires that are not connected withthe wiring-device but serve as feed-through conductors having to betwisted together and then soldered and wrapped with` tape, before vtheelectrician crowds the surplus wire back into the box (at some risk ofloosening some connection just made) and mounts the wiring-device in itsface orice--at some risk of loosening binding-screw connections.

Av further object of my invention is to so construct my novelwiring-umts that each cable section connecting two of them need not belonger than the distance between their centers, with consequent saving'of cable-cost; that splicing, soldering and taping of feed-throughconnections between cable-wires are dispensed with, and that theelectricians work of installing and wiring each unit is simplied andexpedited in other particulars as well, with substantial saving oflabor-time.

Among other objects sought and attained by my invention are: To insuresafety against fire,

rshock-danger, and breakdown, fully satisfying k'tact-carryingchassisthereof, with cover removed, having both "armored and non-memeans forboth reinforcing the units frangible base-structure and interconnectingthe grounding elements" of the cable-sections it handles. which elementsrequire local ground connection in common. Also to construct and arrangethe cable clamping means (used in making such interconnection) for sorigidly and fixedly positioning the cable-ends with respect to the unitsbinding-screw terminals to which the cable conductors must connect, thatloosening oi such connections, during or after installation is fullysafeguarded; and further to provide in appropriate ones of the units thecapacity to handle four sections of cable, of appropriate two-wire orthreewire content; and further to aiord in the different-purpose units ageneral congruence of slim, shallow, elongated casing-shape that willgive desired appearance-value to the line, augment the utility of theunits, and best accommodate mounting of the units on edge surfaces ofbuilding-frame members; and to provide in various of the unitsservice-furniture of novel structure helpful to attainment oi myobjects,

For attainment of said objects and other advantages that willhereinafter appear, my invention consists in the features oiconstruction and' combinations of parts of the wiring-units ashereinafter set forth and claimed; reference being had to theaccompanying drawings wherein I have shown, i'or purposes of fulldisclosure, several typical ones of my line of different-purpose unitsand some typical conditions of their advantageous installation andcooperation in useall of the units so shown being ones that I havei'ound in commercial practice to be desirable, economical and in largedemand.

In the drawings- Figure 1 is a perspective view of a surface wiringinstallation for lighting, served in respective parts by sections ofboth two-wire and three-wire cable, and involving wiring units of myinvention including lamp-receptacles of both keyless" and pull" typesand switches of both three-way and single-pole types;

Fig. 2 is a Wiring diagram of the Fig. l installation, skeletonzing thecurrent-carrying furniture of the several said types of wiring units;

lamp-receptacle, constructed in accordance with my invention- Fig. 10being a. perspective view from the back;

Fig. 11, a transverse cross-section on line I I-I i of Fig. 10;

Fig. 12, a longitudinal section on broken line I2-I2 of Figs. 10 and 13;

Fig. 13. a face view of the furnished base alone;

Fig. 14, a perspective detail oi a terminalcarrying bus-bar thereof; and

Fig. 15, a detail of the pull-switch mechanism housed in the back recessof the base;

Fig. 16 is an exploded view of the current-conductive furniture oi' athi ee-way switch; and

Fig. 17, a corresponding view showing singlepole switch furniture;either furnishing being accommodated by the same base as phantomindicated in dotted lines;

Figs. 18 through 23 show complete structure of the three-way switchdiagrammed in Fig. 16-

Fig. 18 being a central longitudinal section on line I8-i8 of Fig. 19;

Fig. 19, a plan view of the chassis with switch handle and springremoved and the longitudinal Figs. 3 through 8 show a keylesslamp-recep-,

tacle or socket, constructed in accordance with my inventionl Fig.3`being a centrallongitudinal vertical sec- ,tion` through the completeunit, with cover in A, "place, on line 3 3 oi Fig. 5;

Fig.`l4, alcorresponding transverse section. on ".'line 4,-4 of Fig. 3;

. Fig. 5, a face view'of the base-member or contalli'c sheathed cableconnected therewith:

Fig. 6, asection parallel to that of Fig. 3. taken on lineS-S of Fig. 5and with only one end-port wired; Fig. 7', a cross-section on line 'l--loi Fig. 6 witha single wiring-port in use; and

Fig. 8. a perspective view of the back of the unit, showing the metallicreinforcing-andgrounding structure, with one of its clamp-receptivebushings withdrawn from operative position;

Fig. 9 is a section similar to Fig. 4, showing modication to provide arosette, or drop-cordlamp unit identical in most oi its parts with thekeyless lamp-receptacle;

Figs. 10 through 15 show a pull-switch type of bridge member brokenaway:

Fig. 20, a cross-section on line 2U-20 of Fig. 19;

Fig. 21, a cross-section through the switch, on line 2'I-2l of Fig. 18;

Fig. 22, a cross-section on line 22-22 o1' Fig. i9; and

Fig. 23, a cross-section of the three-way switch. on line 23--23 of Fig.18;

Fig. 24 is a plan view, similar to Fig. 19, oi the chassis of asingle-pole switch, which dii.'- iers from the three-way switch only inits contact-provision.

Throughout the drawings, the keyless lampreceptacle as a whole will bedesignated by reierence-letter A; Ai, A-2, etc., used in the wiringdiagrams indicating several such units respectively. Reference-letter Bwill correspondingly indicate in general the pull-switch type oi'lamp-receptacle; C, the three-way type of switch; D, the single-poleswitch, and E, a rosette" for serving a drop-cord lamp. Like reierencenumerals will designate like parts where applied to more than oneparticular embodiment of my invention. Addition of an exponent letter,such as a to a number common to more than one type of unit willspecifically indicate the part bearing that number employed in unit A,and so on.

Some of the structural features germane to my invention, andrelationships between them for joint advantage, are employed in al1 theunits oi my novel line, of which the ones specifically illustratedherein are exemplary;although (as the units shown herein suffice toexemplify) particulars may be varied quite widely, and to considerableadvantage, in applying those gener-al features of construction to unitsoi' dissimilar purposes that, of course, dictate the nature of theirrespective service-furnishings.

In part, the general features common to all units include matters ofproportioning and arrangement of the casings-and especially the basesthereof-to promote the desiderata of economy in manufacture, saving ofelectricians time in installing, utility, and looks; also, equipping thebase with a grounding member and its appurtenances that willinterconnect the grounding-elements of Iall cable-sections serving theunit, whether the cables be armored or of nonmetallic type with specialgrounding wire; and provision insuring that any cable-section longa,soe,sss 3 enough to reach the longitudinal center of the unit (as willbe true of both sections lof an al ready-installed cable cut at thepoint where an additional feed-through" unit, to be installed, willcenter) will be plenty long enough for wiring-up the service-furnitureof that unit by virtue of the terminal-arrangements and bus-connectionsprovided by the service-furniture and their positioning with respect tothe cable-positioning parts of the casing. Other features ofadvantageous relationships will appear from the detailed descriptions ofthe different units shown.

Each unit herein shown has a casing 30 that characteristically is ofrelatively-elongated, narrow, shallow proportioning; such general formconducing to structural and functional advantages as well as tounobstrusive, sightly appearance and to fitness of the unit for mountingon the edge-surface of two-by-four and like-thickness woodenframe-members so universally used. In commercial practice, I find acasing-body cross-section of approximately 13/4 inches width by 11/2inches depth is satisfactory. In different types of units thelength-dimension varies somewhat, but only in keeping with differencesin longitudinal space required by the respective sorts ofservice-furniture employed. Other length factors are substantiallyuniformized in the casings of.

the different-purpose units. Thus, in commercial practice, the differentbase-lengths are with furniture of the unit, mounted chiefly on top ofthe base 3i, is practically all housed in the space Il between saidcasing parts; a suitably shaped aperture I5 in the covers face givingaccess to those parts of said service-furniture (such as switch-handles,socket-shells, and the like) that must be reachable from the outside.

Cable access to the interior of the casing is afforded by end-portingonly, as at 31. The switches VC and D have only a single port in eachend of the casing, on its longitudinal center-line. Other units,including the lamp-handling ones A and B, have twin ports inside-by-side, closely adjoining relation at each end. At the ends of thecasing, the base and cover meet in a plane that bisects the portshorizontally.

Uniform length-components common to the different units begin vat theports, in effect. In the base 3l of each unit a bolster Il, againstwhich a cable may be clamped, protracts each ports curvature inwardly auniform distance to give the cable a long'bearing thereon, vandterminates at an abutment Il against which the cut-back sheath of thecable may be accurately screws at the adjacent end of theservice-furniture of the unit, mounted on the centrallydis posed-fumiture-stand 43, the length of which may vary according to thefurniture it carries.

With the equipped base or chassis" fastened to the wall or framing bymounting-screws 44, accurate de-sheathing, stripping of conductors, andwiring-up may be done very rapidly.

For safeguarding against shockr to the buildings occupants and otherhazards arising from stray currents and static charges, safety-codesrequire that the sheathing oi' all armored cable contained in thebuildings network of circuits must be earth-grounded locally to thepremises; and where non-metallic cable is employed, having a barewiregrounding element enclosed in its fabric sheath, such grounding wiresmust likewise be connected in a network, and given a local ground.

For purposes of interconnecting such grounding elements of either typeof cable, I provide in the base block 3i of each unit a conductivegroundingmember to -be electrically connected with the groundingelements of all cable-sections serving the unit, and I advantageouslyutilize the' cableclamping means associated with each cable port inestablishing electrical connection between said base-carriedgroundingmember and the grounding elements of the cable-sections servingthe 4unit-whether the cable be of armored type or non-metallic type witha grounding wire; both such types of cable being shown as electricallyconnected to cable-clamps in Fig. 5.

Desirably, the grounding member for each sort of unit shown isconstructed to serve also as a reinforcing member for the porcelainbase, arranged to take part of any strain imposed on the unit throughthe cable-sections and clamping means. Particulars of preferredembodiments are different, as between the switch-units shown. having asingle cable port at either end, and the lamp-receptacle units havingtwin ports at each end. I will describe the latter first.

In each of the units shown, the grounding member is a sturdy steel platebedded in the lower portion of the base 3i, the base, when of porcelain,being recessed as at 41 to receive the plate 46 snugly and insulate itcompletely from the service-furniture above it with which the cablesinsulated conductors are .to be connected: said metal plate 4lpreferably being nearly as large as the base and bearing firmly on thelatter near its ends, where connection of the plate with the clampingdevices will be made. Shallow domes 4I formed on the plate are threadedto receive .the cover retaining screws 33, the ends of which may bewithin the dome-recesses.

Where the unit has twin ports at its ends, as in the lamp-receptacles, asingle clamp will serve both, as shown with respect to keylesslampreceptacle A, Figs. 3 et seq. As there shown, the clamp assembly,lll, comprises a cross-yoke Si extending over both cable-positioningholsters 38 on the base 3| and engaged by a centered clamping screw I2under the head of which the yoke may rock somewhat; said screw beingthreaded into a bushing i3 below, the flanged and squared head I4whereof is seated from below in a matching, squared and apertured recessl5 (Fig. 8) of the grounding-and-reinforcing plate 4I, through theaperture of which the bushing passes. Such yoke is desirably providedwith two removable metal shutters Il on its opposite arms, normally toclose or mask the twin ports l1. For carrying such` shutters and fordouble bite on the cable, the clamps cross-yoke il is desirably stampedand then folded to U-shaped section, so as to provide parallel sidesU-connected near their ends and apertured as at 58 in said U-portions todetachably receive the prongs l1' of respective shutters 51. Bysqueezing with pliers the prongs of either shutter 5l, it may bevremoved. Clamping engagement of the yoke with one cable, while theshutter 51 for the twin port remains in place as fulcrum for the yoke,is shown in Fig. 7. Pull stresses and bending stresses fall largely onthe rugged metal parts, protecting the frangible porcelain. And completeinterconnection oi' the grounding elements of all cable sections servinga unit needs only good contact of a clamp with the metal sheath m ofarmored cable M or engagement of its screw with the bare wire n of thenonmetallic type N, as indicated in Fig. 5.

Where a single port is provided in the casing end, as in the switchillustrated in Figs. 18 et seq., a simpler construction serves thegrounding and reinforcing purposes aforementioned; the clamping yoke 5ichaving parallel vertical side bars cross-connected at theirends, wherescrews 52e are passed downward through them to-engage the threadedapertures in upturned ears 58 oi' the grounding member 48 that findaccommodation in recesses 59' molded in the base Il.

Conventional local grounding of a network of armored cables M isindicated at the left oi' Fig. 1.

where grounding member 48 of keyless socket A-I will accommodate thefeeding through them of current to serve those beyond it, is that any ofthem may be wired into an already-installed cable; the cable being cutto receive it at the point where the unit is to be centered. Thus, inthe installation dlagrammed in Figs. l and 2, the keylesslamp-receptacle A-i could be wired into an already-installed main cableM, so as to feed through A-i to the pull-switch lamp-receptacle B-2 onthe ceiling and to other units beyond. And kindredly, in installing theshort second cable M-i-sections of which are to connect switch D-I andlamp-receptacle B--I fo keyless receptacle A-I-a suitable short lengthof cable may be partially cleated in intended place to run alongside themain one and cut at the same point as is said main cable M. Accuratedea-sheathing for proper location of the sheath's end (or the littlefiber end-ferrule commonly used to shield its edges) will easily begaged by matching it against the units abutments 39: and any unit may beproperly wired to the free ends of the conductors so desheathed.

To this end, the terminal binding-screws for each unit mounted on itsfurniture-stand are so constructed and located that' any wire of acablesection properly cut as aforesaid can easily reach from any pointwhere it leaves its sheath to engage any one of the terminal-screws, onthe adjacent end of said furniture-stand; the ends of wires spanningshorter distances to terminalscrews being snipped off accordingly.Further,

each terminal that may o n occasion serve two wires is formed and usedas best illustrated in Figs. 5 and 14, its broad-headed binding-screw 8|being closely flanked by upturned flanges 82 of the conductiveterminal-member or bus B3 so that the two conductors, led to oppositesides of the screw, will run straight along the corners formed by theflanges and both be securely clamped by the screw. Wiring-up isexpedited, and safety is served, by this provision for stemming twowires from the same terminal.

Further. in the mounting of the terminallcarrying busses and associatedparts of their furniture on the furniture-stands, I advantageouslyprovide for locating their terminals at different levels, on terraces,molded in the stand, so that vertical separation may augment theirlateral separation-which the narrowness of the housed space availablefor the furniture-stand, and the employment of the broad, flangedtwowire terminals aforementioned, makes quite meager in some instances.Such variation. in binding screw levels also facilitates distribution ofthe conductors without undue crowding, in the crossing paths they mustoften take through the distribution-chamber 42, in reaching appropriateterminal-screws.

Referring particularly to the keyless type of lamp-recptacle, A, shownin Figs. 3 through 8, it

has three longitudinal bus members 64, B5 and- 86, of the broad-endedconstruction heretofore mentioned, for reception of two conductors; themiddle one being mounted at a higher level than the side ones and beingsomewhat longer than they; said center member 65, as well as the sideones, being a through-connector since its longitudinal separatedend-portions are riveted, as at 68, to the conventional lamp-socketshell 61. To complete the lamp-socket connections, its center-contacttongue 69 is riveted to bus member 66; the remaining bus 64 servingmerely as a through connection between the terminals it carries. v

This structure equips the unit for a very useful diversity ofcircuit-arrangements, including a capacity to handle four sections ofthree-conductor cable on occasion. As shown in circuit in Fig. 2, its'three branching connections of two-wire cable additional to its two-wiremain line connection, enable its own lamp to be controlled fromsingle-pole switch D-i and as well the lamp of neighboring pull-socketB-I on the wall, which can only light when A-I does; while a similarpull-socket B-2 on the ceiling. branched from A|, may be pulled on andoff regardless of the operation of switch D-i.

In a rosette E (Fig. 9) to serve a drop cord lamp, the same porcelainbase 3| may be employed that is used in a keyless lamp-receptacle andwith like range of service` its furniture being changed only by Joiningthe end-portions of middle bus 65 by a connector li located on the underinstead of the upper side of the furniturestand, and by forming the twoside bus members 64e and 66e to provide screw-equipped bindingposts 13to which the lamp-cords conductors may be attached.

Respecting the three-way" and single-pole" switches herein shown andrespectively indicated as C and D, various novel features they have incommon with the lamp-receptacle units of the line have heretofore beenreferred to, but novel particulars of their construction andterminalconnection facilities are of advantage in attainascenso ingobjects of my invention and in enhancing their utility as units of myline.

Both switches C and D are of toggle type with conventional snapmechanism including handle, blade and an interposed snap-spring t2,forming the moving-parts assembly, the switch-cavity S3 in which theyoperate having a single pair of contacm 9d at one end of the cavity inthe single pole switch and opposed pairs dll and 85 in the three-waystructure.

Identical bases will accommodate either the three-way or single-polefurniture, as indicated in dotted lines 3l in Figs. 16 and 17.

In both switches a dual-purpose member llt, extending longitudinally ofthe base over its central portion, between the posts ill at the ends ofthe switch-cavity on which it is securely mounted, is aperturned toreceive the switch handle 8D and serves as a mechanical bridge on whichthe handle fulcrums and which-maintains the moving parts of the switchin assembled relation. Also it serves as a feed-through busrnember oi'the service-furniture, its ends being extended into the upper part ofthe distribution chambers t2 near the end ci the casing and providedwith terminal binding screws 88 and 8c with which conductors of theproximate cable-sections entering the respective end-ports will beconnected to constitute a through 'circuit-connection unbreakable by theswitch.

In the other conductive parts of the simpler, single-pole switch, thetwo switch-blades 8d have binding screw terminals 93 and 9| connectedtherewith at the appropriate ends of the unit, and one said terminal, 9|has a bus connection 92 alongside the switch cavity to binding-screwterminal 93; these several terminals being preferably located at thelevel of the switch cavitys edge, as indicated in Fig. 22, somewhatbelow the level of the bridge-terminals.

In the three-way switch, a binding screw terminal Sc is applied to oneswitch contact 84 and said contact is connected by a bus member Sli tothe longitudinally aligning contact of the other pair 85, which has noterminal-screw of its own. The remaining contact of pair 85 likewise hasno binding-screw of its own and is connected by bus-member 95 with abinding screw 95 at the other end of the furniture stand; said buspreferably running diagonally across the underside of the insulatingbase in a suitable protective groove, and the binding-screw 96 beingpreferably located on a level lower than the others. Remaining contact85 is provided with bindingscrew 9T.

Thus each switch is provided with a line connection not interruptable byoperation of the switch; the single-pole switch being capacitated fortwo-wire feed-through, while controlling a lamp, as indicated at D-Z inFig. 2, where open condition of the single-pole switch has extinguishedthe lamp of keyless receptacle A--3, but current llows via the bridgeand bus 92 to the further pull-switch lamp B3.

In the three-way switch construction, the bridge connection forms partof both circuits controlled by the respective contact pairs, and itselfis uninterruptable.

It will be understood that while I have herein shown with particularitycertain specic, novel embodiments of my invention for purposes of fulldisclosure of preferred forms thereof that I have Vfound in practice tobe desirable and eiective,

it is not intended to limit my invention thereto save as they may beincluded in the scope or" the appended claims.

lclaim:

l. A surface wiring unit in the form oi a lampreceptacle, switch, or thelike, combining functions of an outlet box and a separate wiring devicemounted thereon, such unit comprising, in combination, an elongated,relatively narrow and shallow casing of insulating material havingcable-receptive ports in its end-walls only; service furniture in thelongitudinal mid-portion of said casing suitable for the units specificpurpose and including two longitudinally spacedapart sets o f;terminal-screws respectively positioned suitably for engagement bycurrent-condoctors oi cable-sections that may enter the ports atopposite ends of said casing and are of length to reach only tomid-length thereof; a plurality oi cable clamping means within saidcasing respectively adjacent said ports at opposite ends thereof,adapted to rigidly secure in xed relation to the proximate sets of saidterminals respective sections of ileiiible, sheathed cable having agrounding element and to be electrically connected with such element;and a grounding men ber carried by said casing, insulated from saidservice furniture and electrically interconnecting all said clampingmeans of said unit.

2. A surface wiring unit in the form of a lampreceptacle, adapted lorsurface installation in conjunction with unit-connecting sections ofilexible, sheathed, multiple-conductor cable of lengths to reach onlyfrom center to center of the units they serve, said unit comprising anelongated, relatively narrow and shallow casing of insulating materialincluding a base and a detachable cover jointly providingcable-receiving ports through the casings ends; said base providingwire-distribution chambers positioned inwardly from said ports; andservice furniture suitable for the units specinc purpose arranged in themid-length portion of the casing, Asaid Iurniture including lampengaging contacts and longitudinal straight-through bus-membersextending along said mid-portion of the casing, and each provided nearits ends with terminal-screws located adjacent said respectivedistribution chambers, for connection with conductors of said cablesentering the proximate end-ports, and means connecting said contacts tocertain of said bus-members.

necting sections of flexible, sheathed, multipleconductor cable orlengths to reach only from center to center or the units they serve,said unit comprising an elongated, relatively narrow and shallow casingof insulating material including a base and a detachable cover oi' equallength jointly providing cable-receiving ports through the casings endsand providing wire-distribution chambers positioned inwardly from therespective ported ends; service iurnnzure suitable for the units specicpurpose arranged in the mldlength portion of the casing, sain rurnitureincluding bus-members longitudinally spanning said mid-portion andhaving terminal-screws aajacent said respective distribution chambersfor connection with conductors of cables entering the proximateend-ports; a plurality 'of metallic cable-clamping means between,respectively, the opposite end-ports and the distribution chambersproximate thereto, arranged to rigidly clamp I -within the casing therespective cable in lixed twin ports in opposite walls thereof;

relation to the appropriate said binding screw and to receive inconductive contact therewith the grounding member of such respectivecable; and electrically conductive means on the casing base connectingthe cable-clamping means at opposite ends of the casing and insulated bysaid base structure from conductive connection with said servicefurniture.

4. A wiring-unit, suitable for cooperation, in the surface wiring ofbuildings, with flexible, sheathed cable of a type including a pluralityof service conductors and a grounding element, comprising a chamberedcasing of insulating material, ported for cable-reception and havingseparable base and cover portions; current-handling furniture within andinsulated and supported by said casing and having terminal-screws forconnection with the cable conductors; a grounding member carried by andentirely beneath said base and insulated from said furniture; andcable-engaging means arranged for conductive connection within saidchamber with the grounding element of the entering cable andconductively connected with said grounding member through said base,said cable-engaging means being constructed to clamp the cable againstsaid insulating base.

5. A wiring unit suitable for cooperation, in the surface wiring ofbuildings, with sections of ilexible, sheathed cable of length to reachonly from center to center of the units they serve and of a typeincluding a plurality of service-conductors and a grounding element,comprising a casing having at its ends longitudinal ports for aplurality of cable sections and having a base of frangible insulatingmaterial and a detachable cover; current-carrying furniture Within saidcasing, including terminal screws arranged between the longitudinalcenter of the casing and the end-ports for connection with conductors ofsaid cables; a metallic reinforcing and grounding member carried by saidbase and insulated from said furniture and extending to adjacent allsaid ports; and metal cable-clamping means within the casing adjacentto'said ports and arranged for conductive connection within the casingwith the grounding elements of said cable sections, said clamping meanshaving a tensionscrew in conductive and strain-relieving connection withsaid reinforcing and grounding member.

6. A surface wiring unit combining the functions of an outlet-box.wiring-device and wiresplices, and serving to electrically connecttogether, and to interpose specific-function furniture in circuit with,separate sections of multiple conductor sheathed cablel of lengths toreach only the centers of the units they connect, comprising base andcover members of insulating material forming a chambered casing providedwith three straight-through bus members in said casing in Vspacedinsulated relation to each other and extending to conductor-receptiveproximity to the ports of the opposite walls, each end of each said busmember having conductonengaging means accommodating two conductors;service furniture in said casing electrically connected with two of saidbus members; and respective cableclamping means adjacent said ports inthe opposite walls of said casing.

7. Structure for electrical wiring-units of dif ferent specificfunctions comprising a wiring unit in the form of a lamp receptacle, aswitch or the like, adapted for surface installatibn in buildings inconjunction with unit-connecting sections of multiple-conductor,flexible, sheathed cable of lengths to reach only mid-length of theunits .they connect, said unit comprising an elongated,relatively-narrow and shallow casing of insulating material including a.base and a de tachable cover jointly providing suitable cablereceptiveports through opposite ends of said casing; electrical furnituresuitable for the units specific function mounted in the casing andhaving terminal members, equipped with binding screws at their ends,extending longitudinally from the mid-zone of the base to within reachof the respectively proximate cables conductors; cable-supportingholsters on the base extending inwardly from the cable ports; cablesheath abutments substantially at the inner ends of said bolsters; thebase providing wire distribution chambers intervening between saidabutments and the proximate terminals of said electrical furniture; andcable clamping means associated with each bolster for rigidlypositioning the cable in fixed position relative to its respectivesheath abutment and to said binding screws.

8. A surface wiring unit for installation in conjunction with sectionsof flexible, multiple-con- Y ductor, sheathed cable of lengths to extendonly mid-length of the units they connect, said unit comprising aninsulating casing including base and cover members jointly providing ina wall thereof twin ports in slightly-separated, sidebyside relation;service-furniture for the units speciflo function arranged in the casingand having screw-equipped terminals, each receptive of and arranged tobind the bared ends of two conductors of cables entering said ports;cable supporting means in said base in register with the bottoms of saidtwin ports, and clamping means common to both ports t0 clamp the cableof either or both cable-occupied ports; said clamping means comprising aclamping-screw arranged between the ports, a yoke rockably engaging saidscrew and extending over both cable supporting means on the base, andtwo readily-demount-v able shutters normally carried by opposite ends ofsaid yoke and each normally extending downward substantially to therespective support on said base.

9. A surface wiring unit, of a line of different purpose umts of similarsize and body-shape. combining functions of a switch box and a separateswitch mounted therein and suitable for cooperation with unit-connectingsections of multiple-conductor, flexible, sheathed cable only longenough to reach mid-length of the units it connects, said unitcomprising a relatively long, narrow casing of insulating materialhaving a cablereceptive port at each end; a switching mechanism in saidcasing including at least a pair of contacts and a switch-blade;terminal binding-screws at the ends of said mechanism associated withsuitable ones of said contacts and positioned for respective engagementby conductors of the cable-sections entering said proximate end-portsand serving such terminals; and a complementai, dual-purpose bridge andfeedthrough-bus member extending lengthwise over the switching mechanismto adjacent the aforementioned terminals at the respective ends, andhaving binding screws at both its ends for connection with respectiveconductors of both said cable-sections to provide a feed-throughconnection unbreakable by the switch; said member serving also tomaintain the switch-,mechanisms parts in assembled relation.

10. A surface wiring unit combining the functions of a wall box andwiring device and includ- ,spaced laterally across the base nearer anend wall of the chamber than the said furniture, means connecting saidterminals to said furniture, s. metal plate extending beneath said base,and a cable yclamp electrically connected to said plate and in registerwith said opening.

11. A surface wiring unit combining the functions of a wall boxandwiring device and including a relatively long and narrow base ofinsulating material adapted to be secured to a supporting surface, acover of insulation of substantially the same outline as the base andadapted to form a closed chamber therewith, the end walls of the coverand base each having a notch for register with the notch of acooperating part to form an entrance opening in each end of the chamberfor the sheath of a multiconductor cable, wiring de-1r 'vice conductingparts permanently mounted on and insulated from each other by one ofsaid insulating parts, binding screw terminals spaced laterally acrossthe base in duplicate sets nearer the ends oi' the chamber than the saidwiring device parts, means connecting said` wiring device parts to atleast one terminal of each set, means connecting one terminal of one setto one terminal of the other set, a metal plate extending beneath said'base and a cable clamp near each cable entrance electrically connectedto said plate ior ensuring continuity oi ground across said unit whenmetal sheathed cables are used.

12. A surface wiring unit having a relatively long and narrow base ofinsulating material adapted to be secured to a supporting surface, acover of insulating material oi' substantially the same outline adaptedto rest on and be attached to Ithe base and form therewith asubstantially closed compartment, lamp supporting contacts mountedsubstantially at the center of and insulated by one of said insulatingparts, binding screw terminals in duplicate sets mounted on said baseand spaced nearer the ends of the chamber than the said contacts, meansconnecting the contacts and some of said terminals, registering notchesin the end walls of the cover and base to provide entrance openings formulticonductor cable sheaths, a shoulder inwardly of each openf ing tolimit the entrance ofthe sheath, a chamber between the shoulder andterminals at its end of the compartment to permit distribution ofconductors to appropriate terminals, and means to secure the cover inposition. i 13. A surface wiring unit combining the functions oi a wallbox and wiring device and including a hollow casing of insulatingmaterial and comprising a relatively long, narrow base and a cover oisubstantially the same outline as the base, the end Walls only oi'thecover and base each having a pair of spaced notches for register withcorresponding notches of the cooperating part to iorrn substantiallycircular entrance openings in each end of the casing for the sheaths oimulticonductor cables, current conducting parts including spaced sets oibinding terminals intermediate the ends oi the base, a chamber betweeneach pair of entrance openings and the correspondingset ci terminals forconductor distribution, a hole in the door ci each chamber for amounting screw for the device, and a cover ias- 'tening screw extendingthrough the cover and into the base adjacent each end wall and on a lineintermediate the axes ci said entrance openings.

VICTQR R. DESPARD.

